Sewing machine

ABSTRACT

A thread take-up lever is reciprocable in vertical direction and receives thread from a thread tensioning device. Intermediate the take-up lever and the tensioning device the thread is supplied to a thread guide which is displaceable in parallelism with the movement of the take-up lever between an upper and a lower position. A dial is movable to at least two positions and is connected with the thread guide by linkage means so that the thread guide moves between its upper and lower positions in dependence upon the movement of the dial to the respective positions of the latter. Depending upon whether the thread guide is in its upper or lower position the amount of thread supplied to the take-up lever is varied, that is it is either increased or decreased.

I Umted States Patent [191 [111 3,789,784 Hanyu et al. Feb. 5, 1974SEWING MACHINE 2.997,0|0 8/1961 Hughes 112/254 [76] Inventors q l UPrimary Examiner-George H. Krizmanich igashi-machi, Sanda, Noboru AuomeA t h ls st Kasuga, NO 76125 y, gen ,or irm- 1c ae l'l erami-lchibunkatamachi, both of l 57] ABSTRACT Okyo, Japan A threadtake-up lever IS reciprocable in vertical di- [22] Filed: June 22, 1972rection and receives thread from a thread tensioning [2]] APPL No;266,526 device. Intermediate the take-up lever and the tensioning devicethe thread is supplied to a thread guide which is displaceable inparallelism with the movel l Foreign Application Priority Dam ment ofthe take-up lever between an upper and a June 22, 1971 Japan 46/44513lower position. A dial is movable to at least two positions and isconnected with the thread guide by link- [52] U.S. Cl. 112/246 age meansso that the thread guide moves between its [51] Int. Cl D05b 49/00 upperand lower positions in dependence upon the [58] Field of Search Il2/24l, 242, 243, 246, 254, movement of the dial to the respectivepositions of the 112/255 latter. Depending upon whether the thread guideis in its upper or lower position the amount of thread sup- [56]References Cited plied to the take-up lever is varied, that is it iseither UNITED STATES PATENTS increased or decreased- 2,l84,929 l2/l939Nunn ll2/246 7 Claims, 3 Drawing Figures 1 SEWING MACHINE BACKGROUND OFTHE INVENTION The present invention relates to a sewing machine ingeneral, and more particularly to a sewing machine with a shiftablethread guide and which is capable for use in such stitching operationsas lock stitching, chain stitching and other types of stitchings wheredifferent amounts of the upper thread supplied to the needle arerequired.

Most modern sewing machines can be used for the usual lock stitching aswell as for chain stitching and for other types of stitching. Dependingupon the type of stitching which is to be done, different amounts ofupper thread must be supplied to the needle. For instance, when themachine is used for chain stitching, then less upper thread should besupplied to the needle than if the machine is used for lock stitching.If, therefore, the amount of thread supplied to the needle, and inparticular the amount of upper thread so supplied, is not varied whenthe sewing machine is switched in use from lock stitching to chainstitching, or vice versa, the stitch obtained will not be correct.

The prior art has recognized this problem and has proposed to solve itby supplying such a sewing machine with a special thread guidingattachment, located between the lower positioned thread hook guide andthe thread take-up lever. However, experience has shown that this can betroublesome when the upper thread is passed through the thread guidingarrangement on the way to being threaded into the needle, if theattachment is located in the machine frame and becomes accessible onlywhen a part of the top plate of the machine frame is open. The solutionwhich offered itself to this problem was to locate the thread guidingattachment at the exterior of the machine frame. In that case, however,the arrangement is an impediment when lock stitching is to be carriedout. Moreover, and generally speaking, it has been found that it istimeconsuming and difficult to reset the upper thread to have it passthrough the thread guiding attachment when such a prior-art sewingmachine is to be switched from the lock stitching to the chain stitchingmode, or to reset the upper thread to disengage it from the threadguiding attachment when the machine is to be switched from the chainstitching to the lock stitching mode. Also, it can and does occur thatthe operator forgets to engage or disengage the thread with the threadguiding attachment when the mode of stitching is switched, from one modeto another, and in that case the resulting sitches and seams will beincorrect and aesthetically displeasing.

SUMMARY OF THE INVENTION It is, accordingly, a general object of thepresent invention to overcome the disadvantages of the prior art.

More particularly it is an object of the invention to provide animproved sewing machine which is not possessed of the aforementioneddisadvantages.

Still more particularly it is an object of the present invention toprovide an improved sewing machine in which the supply of upper threadto the needle can be readily varied in dependence upon different typesof stitching operations.

Another object of the invention is to provide such a sewing machine inwhich the adjustment for varying the amount of upper thread supplied tothe needle can be carried out without requiring the operator to exchangeany thread guiding attachment, or to disengage or engage the thread withsuch a thread guiding attachment.

In pursuance of these objects, and of others which will become apparenthereafter, one feature of the invention resides in a sewing machine,comprising a thread take-up lever mounted for reciprocatory movement inan upright path, and a thread tensioning device for tensioning of threadwhich is supplied from a thread source to the take-up lever. A threadguide is mounted for displacement in parallelism with the upright pathbetween an upper and a lower position and is interposed between thetake-up lever and the tensioning device in engagement with the threadsupplied from the latter to the former. A dial is movable to at leasttwo positions and linkage means links the thread guide with the dial sothat the thread guide is displaced to its upper and lower positions inthe thread guide with the dial so that the thread guide is displaced toits upper and lower positions in response to movement of the dialbetween the two positions thereof. In this manner the amount of threadsupplied to the take-up lever can be increased and decreased.

By resorting to the present invention the sewing ma chine can be readilyadjusted for different stitching operations, that is greater or lesseramounts of upper thread can be supplied to the needle withoutdifficulties in dependence upon the requirements of a particularstitching operation, without the operator having to effect anyengagement of the thread with or disengage ment from the thread guidingattachment.

The invention provides for a sewing machine in which the seams which aresewn in the different types of stitching operations will always beproper and tight,

because the amount of thread can be readily adjusted for the particularstitching operations, such adjustment being capable of carrying out bysimple manipulation of a readily used and understood dial.

The inventibn also provides a sewing machine wherein the shiftablethread guide is of simple structure, can be inexpensively produced andreadily as sembled with the remaining components of the machine.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following de scription of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspectiveview of a sewing machine head incorporating one embodiment of theinvention, with certain components omitted for the sake of clarity;

FIG. 2 is a view analogous to FIG. I but illustrating the embodiment ofthe present invention in detail; and

FIG. 3 is a perspective fragmentary detail view of FIG. 2 on an enlargedscale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail it will be seen that in FIGS. 1-3 reference numeral 1 designatesa generally U-shaped thread guide which is provided on the sewingmachine head 100. The thread guide 1 has a pair of parallel wallsdefining between one another a space 2, and a transverse extension 3which projects from one of these walls, The thread guide is also provided in at least one of the walls with a substantially bay-shaped slot2a as a guide entrance for the upper thread 27 supplied from anon-illustrated thread supply source (bobbin or the like) to thesimilarly nonillustrated needle.

A hook-shaped resilient element 4 is provided in the thread guide 1 andin part traverses the slot 20. The guide 1 itself is shiftably mountedon a pair of upright elongated guide plates 7, 7 mounted on the machineframe 6 on one side of the vertical path in which a thread take-up levercan reciprocate The thread guide 1 is positioned between the guideplates 7, 7, and carries on one wall two or more (two shown) spacedprojections or pins 9, 9 which slidably extend into an elongated guideslot 8 which is formed in one of the guide plates 7, 7 and extends inparallelism with the upright path of movement of the lever 5. Thus, thethread guide 1 may be vertically shifted intermediate the guide plates7, 7 between an upper and a lower position, being guided during suchshifting by the displacement of the pins 9, 9 in the slot 8.

The transverse extension 3 ofthe guide 1 carries another projection orpin 10 which is engaged by a forked portion 12 provided at one end of anactuating lever 11. The other end of the lever H is turnably supportedon a fixed shaft 13 mounted in the machine frame 6. This other end oflever 11 is also provided with arm portions 14 and 15 of which theformer is engaged by a tension spring 16 tending to displace the lever11 in clockwise direction (see FIG. 2) whereby the thread guide 1 tendsto be shifted to its upper position along the plates 7, 7 and the slot8.

The arm portion 15 of the lever 11 is connected at 15a to one end 18 ofaconnecting rod 17, the other end of which is designated with referencenumeral 19 and connected at 190 to the upper end of a cam follower lever20. The latter is turnably mounted on a fixed shaft 21 secured in themachine frame 6. A follower portion 200 of the lever is in engagementwith a cam 22 under the action ofthe tension spring 16. The cam 22 issecured on a control shaft 24 which is turnably mounted to extend acrossthe machine frame and which carries at its free end extending outwardlyfrom the machine frame an operating dial 23. The machine has a referencemark 28 (see FIG. 1) and the dial carries in the illustrated embodimenttwo letter designations C and S which can be respectively brought intoregistry with the mark 28 by appropriate twisting ofthe dial 23.

Reference numeral 25 [see FIG. I) designates a thread tensioning deviceof the type known per se and mounted on the other part of the sewingmachine head 100. It can be adjusted by the adjacent operating portionor regulator 26. The upper thread 27 is supplied by the non-illustratedupper thread source and guided through the thread tensioning device 25.It is then placed into engagement with the hoolcshaped resilient element4 of the thread guide 1, passed to the eyelet SI provided at the freeend of the thread take-up lever 5, and from there to the eyelet of thenon-illustrated needle.

When it is desired to adjust the illustrated sewing machine for lockstitching operation, chain stitching operation or the like, the dial 23is turned, resulting in a concomitant turning of the cam 22 on shaft 24,and in a movement of the follower lever 20 around the shaft 21. If thelever 20 is turned in clockwise direction against the action of thespring 16, then the configuration of the cam 22 will result in theconnecting rod 17 turning the lever 11 in counterclockwise directionabout the shaft 13 againstthe action of the spring [6. The result ofthis will be to shift the thread guide 1 to the lower position thereofalong the vertical guide plates 7, 7 and the slot 8. If, on the otherhand, the lever 20 is turned in counterclockwise direction, the lever 11is turned in clockwise direction around the shaft 13 under the action ofthe spring 16 and the thread guide I will then be shifted to the upperposition, the terms upper and lower position always being understoodwith reference to the upper and lower ends of the drawing.

In the illustrated embodiment it will seen that if the dial 23 isrotated so that the mark S is set against the reference mark 28, theguide 1 is shifted to the lower position as shown in the solid lines inFIG. 1. Conversely, if the dial 23 is twisted to place the mark Copposite the reference mark 28, the thread guide 1 is shifted to thebroken-line upper position shown in FIG. 1. If chain stitching is to becarried out with the sewing machine, the thread guide 1 is shifted tothe upper position whereby the thread guide path from the upper threadsupply source to the needle is shortened and the amount of threadsupplied to the needle by the vertical reciprocatory movement of thethread take-up lever 5 is descreased. On the other hand, if lockstitching is to be carried out, the thread guide 1 is shifted to itslower position to thereby lengthen the thread guide path and increasethe amount of upper thread supplied to the needle.

lfit is important to prevent any stitching carried out from causingshrinkage in the material which is sewn, a predetermined configurationof the cam 22 can be used to properly position the thread guide 1 on theguide plates 7, 7 so that the proper amount of upper thread may besupplied to the needle, It will also be understood that although only asingle cam 22 is shown on the control shaft 24, a plurality of cams maybe provided on one and the same shaft, so that they may cooperate withthecorresponding control parts in synchronized or separate relation.

It will be understood that each of the elements de' scribed above, ortwo or more together, may also find a useful application in other typesof constructions differing from the types described above.

While the invention has been illustrated and described as embodied in asewing machine, it is not in tended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention,

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. In a sewing machine, a combination comprising a thread take-up levermounted for reciprocatory movement in an upright path; a threadtensioning device for tensioning of thread which is supplied from athread source to said take-up lever; a thread guide mounted fordisplacement in parallelism with said upright path between an upper anda lower position, said thread guide being interposed between said takeuplever and tensioning device for engaging of thread supplied from thelatter to the former; a dial movable to at least two positions; andlinkage means linking said thread guide with said dial so that thethread guide is displaced to its upper and lower positions in responseto movement of said dial between said two positions, whereby the amountof thread supplied to said take-up lever can be increased and decreased.

2. A combination as defined in claim 1; further comprising wall meanshaving a guide slot extending in parallelism with said upright path; andwherein said thread guide comprises at least two projections extendinginto said guide slot and slidable therein so as to guide said threadguide for displacement of the same.

3. A combination as defined in claim 2, said sewing machine having aframe, and said wall means comprising at least one guide plate mountedon said frame and having said guide slot.

4. A combination as defined in claim 2, said sewing machine having aframe, and said wall means comprising a pair of transversely spaced atleast substantially thread.

1. In a sewing machine, a combination comprising a thread takeup levermounted for reciprocatory movement in an upright path; a threadtensioning device for tensioning of thread which is supplied from athread source to said take-up lever; a thread guide mounted fordisplacement in parallelism with said upright path between an upper anda lower position, said thread guide being interposed between saidtake-up lever and tensioning device for engaging of thread supplied fromthe latter to the former; a dial movable to at least two positions; andlinkage means linking said thread guide with said dial so that thethread guide is displaced to its upper and lower positions in responseto movement of said dial between said two positions, whereby the amountof thread supplied to said take-up lever can be increased and decreased.2. A combination as defined in claim 1; further comprising wall meanshaving a guide slot extending in parallelism with said upright path; andwherein said thread guide comprises at least two projections extendinginto said guide slot and slidable therein so as to guide said threadguide for displacement of the same.
 3. A combination as defined in claim2, said sewing machine having a frame, and said walL means comprising atleast one guide plate mounted on said frame and having said guide slot.4. A combination as defined in claim 2, said sewing machine having aframe, and said wall means comprising a pair of transversely spaced atleast substantially parallel guide plates mounted on said frame and atleast one of which is provided with said guide slot.
 5. A combination asdefined in claim 2, wherein said projections are guide pins.
 6. Acombination as defined in claim 1, wherein said thread guide is ofsubstantially U-shaped configuration and has a main portion and atransverse extension portion; and wherein said linkage means isconnected with said transverse extension portion.
 7. A combination asdefined in claim 1, wherein said thread guide includes a substantiallyhook-shaped resilient element adapted for engagement with said thread.